core/io: Add internal in-memory MemoryIO to all IO layers

Honestly I don't have 100% sure if this is a good idea, the reasoning is that in any IO we'll want to do memory only operations like creating tables etc, so may want a common way to access it

core/io/generic.rs

@@ -3,6 +3,7 @@ use std::cell::RefCell;
 use std::io::{Read, Seek, Write};
 use std::sync::Arc;
 use tracing::{debug, trace};
+use super::MemoryIO;
 
 pub struct GenericIO {}
 
@@ -26,6 +27,7 @@ impl IO for GenericIO {
             .open(path)?;
         Ok(Arc::new(GenericFile {
             file: RefCell::new(file),
+            memory_io: Arc::new(MemoryIO::new()),
         }))
     }
 
@@ -48,10 +50,15 @@ impl Clock for GenericIO {
             micros: now.timestamp_subsec_micros(),
         }
     }
+
+    fn get_memory_io(&self) -> Option<Arc<super::MemoryIO>> {
+        Some(self.memory_io.clone())
+    }    
 }
 
 pub struct GenericFile {
     file: RefCell<std::fs::File>,
+    memory_io: Arc<MemoryIO>,
 }
 
 unsafe impl Send for GenericFile {}

core/io/io_uring.rs

@@ -1,5 +1,5 @@
 use super::{common, Completion, File, OpenFlags, WriteCompletion, IO};
-use crate::{LimboError, Result};
+use crate::{LimboError, MemoryIO, Result};
 use rustix::fs::{self, FlockOperation, OFlags};
 use rustix::io_uring::iovec;
 use std::cell::RefCell;
@@ -35,6 +35,7 @@ impl fmt::Display for UringIOError {
 
 pub struct UringIO {
     inner: Rc<RefCell<InnerUringIO>>,
+    memory_io: Arc<MemoryIO>,
 }
 
 unsafe impl Send for UringIO {}
@@ -78,6 +79,7 @@ impl UringIO {
         debug!("Using IO backend 'io-uring'");
         Ok(Self {
             inner: Rc::new(RefCell::new(inner)),
+            memory_io: Arc::new(MemoryIO::new()),
         })
     }
 }
@@ -207,6 +209,10 @@ impl Clock for UringIO {
             micros: now.timestamp_subsec_micros(),
         }
     }
+    
+    fn get_memory_io(&self) -> Option<Arc<MemoryIO>> {
+        Some(self.memory_io.clone())
+    }
 }
 
 pub struct UringFile {

core/io/memory.rs

@@ -58,6 +58,10 @@ impl IO for MemoryIO {
         getrandom::getrandom(&mut buf).unwrap();
         i64::from_ne_bytes(buf)
     }
+
+    fn get_memory_io(&self) -> Option<Arc<MemoryIO>> {
+        None
+    }
 }
 
 pub struct MemoryFile {

core/io/mod.rs

@@ -40,6 +40,8 @@ pub trait IO: Clock + Send + Sync {
     fn run_once(&self) -> Result<()>;
 
     fn generate_random_number(&self) -> i64;
+
+    fn get_memory_io(&self) -> Option<Arc<MemoryIO>>;
 }
 
 pub type Complete = dyn Fn(Arc<RefCell<Buffer>>);

core/io/unix.rs

@@ -2,7 +2,7 @@ use crate::error::LimboError;
 use crate::io::common;
 use crate::Result;
 
-use super::{Completion, File, OpenFlags, IO};
+use super::{Completion, File, MemoryIO, OpenFlags, IO};
 use polling::{Event, Events, Poller};
 use rustix::{
     fd::{AsFd, AsRawFd},
@@ -167,6 +167,7 @@ pub struct UnixIO {
     poller: PollHandler,
     events: EventsHandler,
     callbacks: OwnedCallbacks,
+    memory_io: Arc<MemoryIO>,
 }
 
 unsafe impl Send for UnixIO {}
@@ -180,6 +181,7 @@ impl UnixIO {
             poller: PollHandler::new(),
             events: EventsHandler::new(),
             callbacks: OwnedCallbacks::new(),
+            memory_io: Arc::new(MemoryIO::new()),
         })
     }
 }
@@ -258,6 +260,10 @@ impl IO for UnixIO {
         getrandom::getrandom(&mut buf).unwrap();
         i64::from_ne_bytes(buf)
     }
+    
+    fn get_memory_io(&self) -> Option<Arc<MemoryIO>> {
+        Some(self.memory_io.clone())
+    }
 }
 
 enum CompletionCallback {

core/io/vfs.rs

@@ -1,4 +1,4 @@
-use super::{Buffer, Completion, File, OpenFlags, IO};
+use super::{Buffer, Completion, File, MemoryIO, OpenFlags, IO};
 use crate::ext::VfsMod;
 use crate::io::clock::{Clock, Instant};
 use crate::{LimboError, Result};
@@ -50,6 +50,10 @@ impl IO for VfsMod {
         let vfs = unsafe { &*self.ctx };
         unsafe { (vfs.gen_random_number)() }
     }
+
+    fn get_memory_io(&self) -> Option<Arc<MemoryIO>> {
+        Some(Arc::new(MemoryIO::new()))
+    }
 }
 
 impl VfsMod {
@@ -65,6 +69,10 @@ impl VfsMod {
             cstr.to_string_lossy().into_owned()
         }
     }
+
+    fn get_memory_io(&self) -> Option<Arc<MemoryIO>> {
+        None
+    }
 }
 
 impl File for VfsFileImpl {

core/io/windows.rs

@@ -3,8 +3,10 @@ use std::cell::RefCell;
 use std::io::{Read, Seek, Write};
 use std::sync::Arc;
 use tracing::{debug, trace};
-
-pub struct WindowsIO {}
+use super::MemoryIO;
+pub struct WindowsIO {
+    memory_io: Arc<MemoryIO>,
+}
 
 impl WindowsIO {
     pub fn new() -> Result<Self> {
@@ -26,6 +28,7 @@ impl IO for WindowsIO {
             .open(path)?;
         Ok(Arc::new(WindowsFile {
             file: RefCell::new(file),
+            memory_io: Arc::new(MemoryIO::new()),
         }))
     }
 
@@ -48,6 +51,10 @@ impl Clock for WindowsIO {
             micros: now.timestamp_subsec_micros(),
         }
     }
+  
+    fn get_memory_io(&self) -> Option<Arc<MemoryIO>> {
+        Some(self.memory_io.clone())
+    }
 }
 
 pub struct WindowsFile {